The invention relates to an auto-bias developing process and apparatus for carrying out the same in an electrophotographic copying machine of the so-called wet developing type.
As a recent trend in the business maintenance work, an increasing number of originals having a colored background is copied by an electronic copying machine. An original having a colored background exhibits a reflectivity which is reduced relatively to that of an orignal having a white background, and is therefore susceptible to a background smearing in the copy obtained. To prevent such a background smearing in the wet developing system, either the amount of exposure or the bias applied to a counter-electrode must be adjusted. In the former case, a troublesome operation is required of a user of the machine to adjust the amount of exposure in accordance with an individual original. In the latter case, there has been a proposal to provide an automatic bias in which the potential of an electrostatic latent image on an image carrier is detected so as to determine a bias voltage applied to a counter-electrode in accordance with the detected potential. However, the arrangement is complex and therefore is expensive.